Project Abstract This application will fund a new, research dedicated, Siemens 3T Prisma MRI scanner. Acquiring this scanner will have an immediate substantial positive impact on the NIH funded research of a large group of researchers and the long range biomedical research goals of the institution. The specifications of the Prisma are substantially superior to our existing decade old Siemens 3T Trio, and the new scanner will provide an immediate improvement in the quality of research MRI that is able to be acquired at our institution. Additionally, current MRI equipment is used for both clinical and research imaging, which creates logistical challenges in scheduling research participants. Schedule overruns and urgent needs of emergency patients sometimes delay or displace scheduled research scans, increasing the difficulty in conducting high quality research studies. BCH carries out over 14,400 clinical MRI scans every year, with a growing wait list for both sedated and unsedated MRI. Growing clinical volume increases the logistical challenges of providing for research MRI time on our existing equipment. Pediatric MRI research is a major focus across Boston Children's Hospital. Since January 2014, Principal Investigators from over a dozen departments at BCH have held imaging study awards, with a total NIH award amount more than $57 million. These projects have provided unprecedented 1) capabilities to study disease mechanisms 2) techniques that enhance the detection and characterization of disease, and 3) innovative new interventions for disease treatment. BCH research activities span the spectrum from fundamental contributions in basic science of acquisition physics, through translational research that has brought innovation into everyday practice, to clinical research that is revolutionizing our ability to prevent, diagnose, and treat disease. Boston Children's Hospital has a mission to provide the highest quality health care and to be the leading source of research and discovery while educating the next generation of leaders in child health. We are New England's regional referral pediatric center and a safety net hospital for the most critically ill children and those from low-income families. We partner with the community to address the most pressing health care needs in surrounding neighborhoods. The hospital trains more pediatricians and has the largest research program of any other pediatric hospital. As a not-for-profit, all of the hospital's resources go toward supporting these goals. The projects of the Users described herein will require approximately 80% of the useable time available on the scanner, and the remainder would be used for exploratory research and new directions. The scanner will be housed and managed within the Research MRI Core of the Department of Radiology at BCH, and will remain a primary research resource for a large group of imaging scientists. The instrument will be supported by an established group of MR imaging experts and support staff. A comprehensive plan has been developed for the financial and technical support of the system as well as for its management, and the system is assured of strong institutional support and oversight.